Combination precision grinder and caliper



Jam. 23, 1940. H. B. BARRETT 2,187,962

COMBINATION PRECISION @BINDER-AND QALIPER Filed oct. 14, '193e' 2 sheets-sheet 1 Jan. 23, 1940. H. B. BARRETT 2,187,962

' COMBINATION PRECISIN GRINDER AND CALIPER Filed 0G12. 14, 1936 2 Sheets-Shee'l 2 'Patented Jan. 23, 1940 UNITED STATE COMBINATION PRECISION GRINDER `AND CALIPER Harry B. Barrett, St. Louis, Mo.

Application October 14, 1936, Seal No. 105,473

17 Claims.

This invention relates generally to tools and devices for grinding cylindrical surfaces and, more particularly, to a certain new and useful improvement in tools or devices especially, though not exclusively, adapted for the grinding of the linings of. brake-shoes and the like.

As stated in Letters Patent No. 2,631,357, is-

sued to me on February 18, 1936, automobile brakes usually comprise cylindrical drums rigidly xed to the wheels and expandible and contractible shoes suitably co-operably mounted pivotally with respect to the drums for applying braking pressure to the drums and hence also to the wheels. For applying such pressure, the shoes are lined with suitable fabric or other friction. material, such as asbestos strips, and for obtaining the maximum of braking eiliciency, it is essential that the shoes not only be accurately positioned, but also that the respective drumengaging faces of the linings have precise and accurate curvature relatively to the cylindrical faces of the respective drums.

1 My present invention has hence also for its primary object the provision of a portable tool that may be readily mounted operatively with respect to the particular brake-shoe and. its linin'g or otherwork, and which is conveniently operable for grinding the brake-shoe linings to conform accurately and precisely with the radial dimension of their companion drums for obtaining the maximum braking eiciency.

My invention has for another object the provision of a grinding tool having a relatively wide range of radial axial and angular adjustments for accurately disposing the abrading-rnember of the tool for effecting the desired grinding operations in a`plane approximatelytangential to the surface being ground. l My invention has for still another object the provision of a grinding tool which may be readily and adjustably fitted on tapered automobile axles and spindles of Various types and sizes.

My invention has for a further object the provision of a combined tool of. the kind mentioned,-

which may also be utilized with facility as a caliper in setting the lining-ground shoes to the desired drum-clearance for effective braking operation. My invention has for an additional object th provision of a combined grinding and calipering tool in which the grinding element `of the tool may be set to a measurement obtained from the brake-drum or other cylindrical surface into which the brake-shoe, or other surface being ground, is to be fitted.

My present invention also contemplates the irnprovement generally of the tool illustrated and described in my said Patent No. 2,031,357, and with all these and other objectsin View, my present invention resides in the novel features of form, construction, arrangement, and combination of. parts presently described and pointed out in the claims.

In the accompanying drawings (tw'o sheets),

Figure 1 is an elevational viewv of a grinding tool constructed in accordance with and embodying my present invention, showing the tool in operative grinding position on an automobileaxle; y

Figure 2 is anenlarged partially broken elevational cross-sectional View of the axle-adapter of the tool;

Figure 3 is an enlarged partly broken end elevational view of the axle-adapter;

Figure 4 is a fragmentary circumferential sectional view of a brake-drum, illustrating the use ofthe tool-caliper for obtaining the precise radial 'dimension of a particular drum;

Figure 5 is an elevational View of the combined tool and caliper positioned for setting the grinding-wheel of the tool accurately to the drum dimension obtained on the caliper;

Figure 6 is a .fragmentary elevational view of the tool, showing the grinding-wheel set for grinding at an angle to the surface of the brakeshoe; and

Figure 'l is a fragmentary rear elevational View of the grinder head shown in Figure 6.

Referring now more in detail and by reference characters to the' drawings, which illustrate a preferred embodiment of the tool, A designates a portion of a brake base-plate, on which operably mounted in a conventional manner about the axle Bis the brake-shoe assembly C.

The grinding-tool proper D` comprises a frame including a bearing member in the form preferably of. a barrel I for mounting of the tool for oscillatory or rotatory movement for lininggrinding purposes on the axle B. llorenabling convenient mounting and securing of the barrel Il on the axle B, the barrell, as shown, isrpreferably of split-type and provided with suitable diametrically expanding and contracting means including a wing-nut and bolt-assembly 2 mounted in a registering pair of ears 3 preferably formed integrally on the barrel I.

The barrel l is also provided with a pair of axially spaced bosses or ears 4 and 5 internally drilled to provide a sliding bearing for a guiderod 6. Similar bosses or ears .1 and`8 arepreferably integrally formed axially inwardly along the peripheryof the barrel I and are internally drilled to form a sliding bearing for a second guide-rod 9, as best seen in Figures l and 5.

Mounted rigidly on, and extending laterally between, the lower extremities of the guide-rods 6 and 9, is an end plate IIJ, which is provided with a centrally drilled bearing II, through which operably is lengthwise disposed a lead-screw I2 having a calibrated hand-wheel I3 rigidly mounted on its lower end, the screw I2 extending upwardly, reference being made to Figures l and 5. andoperatively engaging an internally threaded nut-shoulder I4 preferably integrally formed on the periphery of the barrel I, as also best seen in Figure 5.

Rigidly mounted at the upper extremities of the guide-rods 6 and 9, is a grinder supporting head I5, which is provided with a clearance recess I6 for a purpose presently described. And forming part of head I5, is a plate-like enlargement or continuation I5 provided longitudinally with a groove or slideway I1, centrally of which is a parallel slot I8 having a notch I9 in its lower edge, as best seen in Figure 6.

The guide-rods 6 and 9 and the lead-screw I2 are preferably disposed in a single plane, which is parallel to the plane of the radius of the barrel I,.so that, when the screw I2 is turned in the nut I4 by rotation of the hand-wheel'l3, the guide-rods 6, 9, will be lengthwise shifted and the head I5 and accompanying structure, pres ently described, will correspondingly be moved radially toward or away from the barrel I.

Suitably mounted in a casing or housing 2i), is a 4prime mover in the form preferably of an electric motor 2I, whose shaft is operably connected, through a conventional train of gears, not shown, to a grinder-shaft 22 rotatably disposed in a bearing 23 formed on the under face of 'the housing 20, and suitably mounted on the free or projecting end of the shaft 22 is a grinding or abrading-member preferably in the form of a face-wheel or flat disk 24, themotor 2| being adapted for electrical connection through a toggle switch 25 and a flexible electric conduit, the latter not being shown, to asuitable source of electrical energy.

Preferably integrally joined to, and forming substantially a part of, housing 20, is a faceplate 26 adapted normally for ilatwise-impinging engagement with the head-plate I5', the plate 26 being provided longitudinally with a tongue 21 adapted to lit the groove or slide-way I1. A set-screw 28, having a knob 29 rigidly mounted on its free end, is threadedly disposed in the tongue 21, as shown in Figure 6, and is so arranged as to pass through the slet I8 in the groove or slide-way I1, the screw 28 being of such relative size as to also fit the notch I9, as shortly more fully appears.

Thus, it will be seen that, by turning the knob 29 and loosening the set-screw 28, theplate 2'6 and housing 20 may be shifted relatively to the head I5 and its continuation I5 for adjustably disposing the abrading or grinder disk 24 toward or away from the work in a line parallel to the axis of the barrel I. And if it is desired to perform a grinding operation in a plane angularly disposed to the plane of the axis of the barrel I,`the set-screw 28 may be loosened a sufficient distance to allow the tongue 21 to be completely withdrawn from the groove I1, whereupon the set-screw 28 may be dropped into the notch I9 and the head 20 pivotally swung to the desired angular position, in which adjustedposition it may be securely held by finally tightening the set-screw 28. Thus, the abrading-disk 24 is adjustable relatively to the frame-head I6 for grinding a plurality of surfaces about the axial 5 line of the barrel I in a relatively wide range varyingvfrom a surface perpendicular to the axis of the barrel I to a surface whose tangential planes are parallel to said axial line. And since the grinder-disk 24 is of comparatively large di- 10 ameter, the horizontal adjustment of the grinder head or housing 20 would, in the absence of recess I6, bring the disk 24 at its periphery up against the forward face of the supporting head I5. However, such movement of disk 24 is well accommodated by the recess I6, which permits a wide range of adjustments of the disk 24, grinder-disk 24 freely rotating within the clearance recess I6 when the grinder head 20' is rearwardly adjusted.

The head or housing 20 is also provided with a preferably integrally formed lock-pin retaining shoulder 30, in which is slidably disposed a vertically movable lock-pin 3|, which may be shifted downwardly into locking engagement with the upper face of the grinder-disk 24 and held rigidly in such position by tightening a setscrew` 32, the grinder-disk 24 being therebysretained rigidly against rotation, for a purpose presently to be described,

Co-operable with the grinding tool proper, is a brake-drum caliper E comprising a centrally disposed annular sleeve 33, extending radially outwardly from which, are diametrically opposed arms 34 and 36, the sleeve 33 being provided 35 with preferably diametrically opposite segmental bosses 36, 31, having an outer diameter equivalent or equal to the inside diameter of the barrel I, whereby the sleeve or body-portion 33 is co-axially engageable with the barrel I.

Preferably integrally 'formed on the arm 34 for slidably supporting a contact-bar 38, isl a bearing 39 having a preferably integrally formed lateral extension 40. Similarly formed on the arm for slidably supporting a second contact-bar 4I, is a bearing 42 also having apreferably integrally formed lateral extension 43, the bearing 42 being longitudinally split and provided with a clamping screw 44 for clampingly retaining the bar 4I in any predetermined set 50 position. Rotatively mounted in,.and extending between, the extensions 40, 43, is a two-directional screw 45 having a right-hand thread extending from the middle to one end thereof an'd a left-hand thread extending from the vmiddle to the other end thereof. Rigidlymounted on and at the middle of the screw 45, is a knurled and calibrated turning knob 46, and xed on the inner extremities of the contact-bars 38, 4I`,are laterally extending traveler-arms 41, 48, respectively, having threaded engagement with the right-hand and left-hand threaded portions, respectively, of the screw 45. Thus, it will be o bvious that, when the screw member 46 is rotated upon a turning of the knob 46, the contact-bars 38A and 4I will be lengthwise translated or shifted toward or away from each other in the bearings 39, 42, respectively.

For further accuracy in setting the caliper, a graduated scale 49 is provided on the arm 35, and an indicator arm. 50 is correspondingly provided on the traveler-arm 48. Similarly, an indicating pointer 5I, for the graduations on theknob 46, may be provided on the sleeve 33.

Also co-operable with and forming substan- 'u` tiallya part of the tool, is an adapter 'F for enabling convenient mounting of the tool with ab.

solute assurance of concentricity of grinding upon axles and spindles having different degrees of taper. As best seen in Figures 2 and 3, the adapter F comprises a substantially two-part cylindrical sleeve, one member or section 52 of which is formed with a centrally disposed, externally threaded portion 53 of substantially larger outside diameter than the normal outside diameter of the sleeve-section 52. Disposed annularly about the section 52 in ythe forward end of its portion 53, is a plurality of radially reciprocable pins 54, each of which is provided adjacent its outer end with an opening or channel, as at 54', through which is projected a rod or leaf spring 55 for normally yieldingly retaining the particular pin 54 radially outwardly from. the center or axis of the sleeve-section 52, each spring 55' having its free ends loosely disposed in a channel formed in the peripheral face of the sleeve-portion 53, as bes't seen in Figure 3. At their respective outer ends, the pins 54 are beveled, as

best seen in Figure 2, and encircling the sleeveportion 53 for engagement at its internally inclined surface 55 with the beveled ends of the pins 54, is a wedge-ring 51, an internally threaded bearing collar or ring 58 'being' abuttingly threaded on the sleeve-portion 53, so that,'upon rotation of the collar or ring 58, the attendant' longitudinal translation thereof will cause longitudinal translation of the Wedge ring 51 and thereby, through interaction between the inclined surface 56 and the beveled ends of the pins 54, produce radial translation of the pins 54.

59 designates the second sleeve-section, which has the same external diameter as the threaded sleeve-portion 53 and, for a portion of its length, has the same internal diameter as the external diameter of the .sleeve-section 52 to fit engagingly thereupon, all as best seen in Figure 3, the sleevesection 59 being provided with external threads as at 59', preferably of the same pitch as the external .threads 53' on the sleeve-portion 53, and being also provided with a set-screw 60 for engagement with the sleeve-section 52 for detachably securing the sleeve-sections 52 and 59 together.

The sleeve-section 59 is similarly provided with an annular series of radially reciprocable, springpulled pins 6I, which likewise engage a sleeve encircling wedge-ring 62, which latter is, in turn, similarly actuated by an internally threaded bearing-collar 63 having threaded adjustable engagement with the sleeve 59.

The wedge-rings 51,62, and bearing-rings 58, 63, at their outer peripheral surfaces, are machined to an outsidediameter exactly fitting the inside diameter of the-barrel I, so as to provide a bearing surface on and about which the barrel I may rotate.

Now, it will be noted that the distance between the wedge-rings 51, 62. is substantially fixed between definite limits. If hence, in practice, it becomes necessary to mount the barrel I on a shorter spindle or shaft than that shown in'. Figure 2, the set-screw SII may be withdrawn and the sleeve-section 59 removed from one end of the sleeve-section 52 and reversibly placed on and over the opposite end thereof, as shown by dotted lines at G in Figure 2. Thus, the adapter F conveniently enables the mounting of the barrel I on not only different length, but also on diierently tapered, axles or spindles.

In use and operation, any particular wheel is their respective outer ends touch the inner peripheral face of the brake-drum W, the clamp-y screw 44 being then tightened for securing the bars 38, 4I, of the calipers E in such adjusted measuring position. The calipers E are then withdrawn from the brake-drum W and operatively connected With the tool by inserting the sleeve vengagement bosses 36, 31, into the forward end of the barrel I, as clearly illustrated in Figure 5. The locking-pin 3I is thereupon shifted into locking engagement with the grinder-disk 24 for retaining the same against rotation. The hand-Wheel I3 is then turned in a proper direction, thereby rotating the lead-screw I2 and lengthwise actuating the guide-rods 6, 9,. a suflcient distance to bring the grindingface' of the disk 24 into light Contact with the presented end of the bar 4I of the calipers E. For accuracy and precision, in adjustment, the sleeve 33 of the calipers E should be placed in the barrel I in such manner that the axis of the contact-bars 36, 4I, lies in a plane parallel to the plane of the guiderods 6, 9, and, further, that the contact-bar 4I preferably touchthe center portion of the grinding face of the grinder-disk 24.

The disk 24 being thus radially located with respect tothe barrel I, the adapter F is placed over the axle B and the threaded collars 58, 63,' then turnedin respectively proper directions Ias to cause outward translation of the respective Wedge rings 51, 62. Thereupon, the ring 51 will be translated or shifted longitudinally forwardly over the sleeve-portion 53 until, under the Wedging action of its face 56, the pins 54 have been moved radially inwardly into impinging engagement with a portion of the axle B. Likewise, the

ring 62 will be translated longitudinally forwardly until the pins 6I are, in a similar manner, moved radially inwardly into impinging engagement with another portion of the axle B. `The barrel I is then placed over the adapter F, whose rings 51, 58, 62, 63, thus, irrespective of the taper of the particular axle or spindle, provide an even bearing for the barrel I in subsequent grinding rotatory or oscillatory actuations of the tool, the nut 2 being tightened sufliciently to provide proper freedom ofA movement of the barrel I about the adapter F.

The lock-pin 3I is now withdrawn to permit free rotation of the grinder-disk 24, and the knob 29 turned for loosening the set-screw 28 disk 24 will thereupon rotate in a plane exactly tangential to the precise inside diametrical dimension of the brake-drum W, and, as the barrel I is rotated on and about the adapter F, the tool will describe a cylindrical path exactly concentric with the axis of the axle B. Thu-s, the tool asa whole may be conveniently moved rotativelyfon and about the adapter F with the disk 24 in 4started by turning on the switch 25. The grinderrotative abrading contact with the surface of the brake-liningtc, a perfectly fitting brake-lining surface resulting.

A predetermined measured amount of clearance between the brake-drum W and the surface of the brake-shoe lining c may be readily obtained, if desired, by rotating the hand-wheel I3 a predetermined amount, as indicated on the graduations thereof, after the setting with the calipers E has been completed.

It will be evident that the present tool provides for the accurate and precise fitting of the brakelinings, eliminating guesswork, trial, and error methods, and the necessity for returning the automobile for second adjulstments. 'Ihe tool, furthermore, does away with unwieldly practices, such as the use of dummy drums and internal adjusting tools. Finally, the present tool, in one operation. centralizes, grinds, and adjusts the brake-shoes to exact drum-size and enables speedy exact alignment of the shoes with the drum surface after the shoes have been restored to operative position on the car.

It will be understood' that changes and modifications in the form, construction, arrangement, and combination of the several parts of the tool may be made and substituted for those herein shown and described without departure fromthe nature and principle of my invention.

Having thus described my invention, what I claim and desire to secure by Letters Patent is,

1. In a grinding-tool, in combination with a bearing. a frame mountable on the bearing for, rotatory movement, and grinder-means including an abrading member mounted on the frame for traveljcn rotatory movement of the frame, in acircular path concentric about the axial line of the bearing, said abrading member having a flat grinding face adjustable relatively to the frame and bearing -for grinding a plurality of selected surfaces about said axial line in a range varying from a surface perpendicular to said line to a surface the tangential planes of which are parallel to said line.

2. In a grinding-tool, in combination with a bearing, a frame mountable on the bearing for `rotatory movement, said frame including a head,

grinding-means including a plate andv a rotary abrading member having a flat grinding face, and

means for adjustably securing the plate to the head, the abrading member being adapted for travel, on 4rotatory movement of the member, in

`a circular path concentric about the axial line of the bearing and the plate being adjustably shiftable relatively to the headv for disposing said grinding face of the abrading member for grinding a plurality of selected surfaces about said axial line 'in a range varying from a surface perpendicuar to said line to a surface the tangential planes of which are parallel to said line.

3. In a grinding-tool, a barrel, grinding-means supported by the barrel, and means for mounting the barrel on a shaft for movement of the grindlng-means in a circular path concentric about'the axial line of the shaft, said mounting means including a sleeve for disposition on and about the shaft, an annular series of pins disposed for radial reciprocation in the sleeve, means for normally yieldably urging the pins radially outwardly from the Vaxial center of the sleeve, a wedge-ring movable longitudinally onthe sleeve for shifting the pins simultaneously inwardly of the sleeve f or impinging engagement with'the shaft, and a bearing ring'having threaded engagement with the s leeve for shiftably actuating the wedge-ring on the sleeve.

4. In a grinding-tool, a barrel, grinding-means supported by the barrel, and means for mounting and about the shaft, said section having .a centrally enlarged externally threaded portion, an externally threaded second sleeve-section counter-bored for disposition partially on and about the first sleeve-section and partially on and about the shaft, means for detachably securing the second sleeve-section to the first sleeve-section, annular series of pins disposed for radial reciprocation in each of the sleeve-sections, means for normally yieldably urging the pins radially outwardly from the respective axial centers of the sleeve-sections, wedge-rings movable longitudinally on the respective sleeve-sections for shifting the pins inwardly oi the sleeve-sections for impingingengagement with the shaft, and a pair of bearing-rings having threaded engagement with` the sleeve-sections for shiftably actuating the respective wedge-rings.

5. In a grinding-tool, a barrel, grinding-means supported by the barrel, and meansfor selectively mounting the barrel for rotationV on different length spindles, said means including a sleeve having cooperable sections for disposition on and about the particular spindle and one of said sections being reversibly engageable with the other section.

6. In a grinding-tool, a barrel, grinding-means supported by the-barrel, and means for selectively mounting the barrel for rotationon different length spindles, said means includinga sleeve having cooperable sections for disposition on and about the particular spindle and one of said sections being reversibly engageable with the other section, and bearing rings Idisposed on and about the sleeve-sections.

7. In a grinding-tool, a barrel, grinding-means supported by the barrel, and means for selectively mounting the barrel for rotation on different length spindles, saidA means including a sleeve having externally threaded vco-operable sections for disposition on and about the particular spindle, one of said sections being reversibly engage' able with the other section, means for detachably securing said sections in engaging relation, and bearing rings adjustably threaded on the sleeve-sections.

8. In a device of the character described, an adapter for mounting a rotatory barrel on a shaft comprising a sleeve for disposition on and about the shaft, an annular series of pins disposed for radial reciprocation in the sleeve, means for normally yieldably urging the pins radially outwardly from the axial center of the sleeve, a wedge-ring movable longitudinally on the sleeve for shifting the pins simultaneously inwardly of the sleeve for impinging engagement with the shaft, and a bearing ring having threaded engagement with the sleeve for shiftably actuating the wedge-ring on the sleeve.

9. In a device of the character described, an adapter for mounting a rotatory barrel on a shaft comprising a first sleeve-section for disposition .on and about the shaft,'said section having a for radial reciprocation in each of the sleevesections, means for normally yieldably urging the sleeve-section, annular series of pins disposed l 5 being drivingly connected thereto, said grinding pins radially outwardly from the respective axial centers of the sleeve-sections, wedge-rings movable longitudinally on the respective sleeve-sections for shifting the pins inwardly of the sleevesections for impinging engagement with the shaft, and a pair of bearing-rings having threaded engagement with the sleeve-sections for shiftably actuating the respective wedge-rings.

10. In a grinding-tool, a barrel, grindingmeanssupported by the barrel, and means for mounting the barrel on a shaft for movement of the grinding-means in a circular path concentric about the axial line of the shaft, said mounting means including a sleeve for disposition on and about the shaft, an annular series of pins disposed for radial .reciprocatlon in the sleeve, means for normally yieldably urging the pins radially outwardly from the axial center of the sleeve, pin-actuating means movable longitudinally on the sleeve for shifting the pin simultaneously inwardly of the' sleeve for impinging ensagement with the shaft, and locking means cooperable with the actuating ring for preventing unauthorized movement thereof.

11. In a grinding-tool, a barrel, grindingmeans supported by the barrel, and means for mounting the barrel on a shaft for movement of the grinding-means in a circular path concentric ab'out the axial line of the shaft, said mounting means including a pair of detachably connected co-axial sleeves for disposition on^and about the shaft, each of saidsleeves having an annular series of pins disposed for radial recip- `rocation therein, means for normally yieldably urging the pins radially outwardly from the axial center of the sleeve, and means associated with` each series of pins for shifting the pins simultaneously inwardly of the sleeve for impinging engagement with the shaft.

12. In a grinding-tool, a barrel, grindingmeans supported by the barrel, and means for mounting the barrel on a shaft for movement of the grinding-means in a circular path concen-` tric about the axial line of the shaft, said mounting means including a sleeve for disposition on and about the shaft, an annular series of pins disposed for `radial reciprocation in the sleeve, means for normally yleldably u rging the pins radially outwardly from the axial center of the sleeve,- and pin-actuating means movable longitudinally on the sleeve forshifting the pins si-l multaneously inwardly of the sleeve for, impinging engagement with the shaft.

13. In a grinding-tool, a barrel, 'means for mounting the barrel on a shaft for rotatory movement therearound, a frame mounted on the side of the barrel and extending laterally outwardly therefrom in a plane tangential to said barrel and being provided at its outer extremity with a cross-frame having a hat face parallel to said tangential plane, an electric motor mounted on the cross-frame for shiftable movement along the flat face thereof, and grinder means mounted on the motor for bodily movement therewith and means including a fiat face-plate grinder having a shaft the axis of which lies in the same plane of the barrel axis.

14. In a grinding-tool, a barrel, means for mounting the barrel on a shaft for rotatorymovement therearound, a frame mounted on the side of the barrel and extending laterally outwardly therefrom in a plane tangential to said barrel and being provided at its outer extremity with a cross-frame having a at face parallel to said tangential plane, said cross-frame extending laterally outwardly from the frame in the formationof an off-set arm, and power-driven grinding means mounted on lsaid at face for shiftable movement thereacross, said grinding means including a flat face-plate grinding disk operatively mounted on a shaft having its axis permavnently disposed in the plane of the barrel aids.

15. In a grinding-tool, a barrel, grindingmeans supported bythe barrel, and means for 'xting the barrel on a shaft for movement of the grinding-means in a circular path concentric about the axial line of the shaft, said mounting means including a pair of operably connected relatively shiftable co-axial sleeves for disposition on and aboutthe shaft, each of said sleeves having an annular series of pins disposed for radial reciprocationtherein, means for normally yieldably urging the pins radially outwardly from the axial center of the sleeve, and means associated with each series of pins for shifting the pins simultaneously inwardly of the sleeve for impinging engagement with the shaft.

1 6. In a grinding-tool, a barrel, grinding means supported -by the'barrel, means for` selectively mounting the barrel for rotation on spindles of diiferent lengths and different taper, said means-4 "-.including a sleeve having two cooperable sections for disposition on and about'a particularv spindle, spindle engaging and centering means within eachof said sections, one of said sections being endwise shiftable with respect to the other section for varying the relative disposition of the spindle engaging and centering means of said sections, means for securing said sections together i desired shifted relation, and bearing means disposed on and about said sleeve sections for rotative supporting engagement with said barrel.

17. In a grinding-tool, a barrel, grinding Ameans supported by the barrel, means for selectively mounting the barrel for rotation on spindles of .diiferent lengths and different taper, said means including a sleeve having two cooperable sections for disposition on and about a particular spindle, spindle engaging and centering means Within each of said sections, one of said sections having a reduced portion and the other of saidsections being telescopically tted upon and slidably shiftable on said reduced portion, means for securing said sections together in desired shifted relation, and bearing means disposed on and about said sleeve sections for rotative supporting engagement with said barrel.

V HARRY B. BARnm'r. 

